For many years, the blind and the visually impaired have relied on braille as a major means to read text information. Today there are multiple braille displays allowing vision impaired users to better communicate with their environment. The machines that use computers to convert digital text to braille codes to provide such vision impaired users, the opportunity to use the internet and other electronic devices. The existing braille displays, for example, normally consist of 20-80 characters. Each character will be represented by the position of 6 to 8 pins, where each pin is either elevated or retracted. Therefore, each pin will require an actuator to facilitate their respective movement. Thus, each braille display will require a minimum of 120 actuators, or any another similar type of elevating and retracting mechanisms, which can be costly.
Further, since there are too many number of moving parts, the lifetime of the machine is reduced. Another disadvantage includes costly and time-consuming maintenance. In a case, if one of the components malfunction, the reliability of the braille information itself could be compromised. These conventional braille displays normally use the piezoelectric principle to move the pins in an upward and downward direction. The piezoelectric effect is reliable and energy efficient, but the cost of each piezoelectric crystal is $6 to $10 (Dollars), and therefore the overall final cost incurred is, for example, from about $2,000 to $8,000. Therefore, there is a need for a refreshable braille display system to overcome the above-mentioned issues.
However, most of the proposed methods in the art are complex, costly and space consuming, or bulky. Further, due to the increase in the number of mechanical parts, the probability of failure increases with the implication of increase in the repair and maintenance cost. In the old conventional displays, the braille letters, which consist of a specific number of characters, are juxtaposed, and the visually impaired reader can read the text by touching the characters from left to right. In another group of braille displays that are being developed as prototype, employs continuous refreshing of braille cells for reading texts, for example, U.S. Pat. No. 6,776,619 B1, and U.S. Patent No 0011816 A1.
In these displays, the braille cells are embedded on a wheel, and with their rotation of the wheel, the braille characters are displayed in their specific order. However, in these references and other similar applications, in order to adjust pins of each braille cell, the methods employed are costly, complex with over-utilization of space, and of short life span. Considering the above-mentioned issues, there is a need for a refreshable braille display, or a refreshable tactile display apparatus that is low cost, lightweight, and more reliable.